Day 1
The Omega unit started an experiment yesterday, about how the digestive system works. The process starts in the mouth, where you chew up all your food. Then, enzymes in your saliva break down the food even further. After this, the chewed-up food travels down our esophagus. There is a little flap called the epiglottis that prevents the food from entering our windpipe. The next step is our stomach. In the stomach, there is mechanical digestion and chemical digestion. Mechanical digestion is when food is physically broken down, like when you chew your food. Chemical digestion is when your body breaks down food with the aid of acids and other chemicals. The stomach churns and rolls all our food around (mechanical) while the acid in our stomach breaks them down (chemical). The chemicals in our stomach are a mix of two things: hydrochloric acid and pepsin, which is an enzyme. Our goal in this experiment was to replicate the digestion in our stomach. We had four test tubes, each with a different combination of food, (in this case, egg) hydrochloric acid and pepsin. We left these mixtures in the classroom overnight.Day 2
Today was Day 2 of our digestion experiment. We took our test tubes out again and tested them on litmus paper, which is a special type of paper that reacts to acidic substances. It is kind of like the iodine when it comes in contact with the starch. We also observed the appearance of the test tubes. Most of them didn't have any reaction from the day before, but in one of them (the combination of food+pepsin+hydrochloric acid) the egg had dissolved a bit. This led the class the conclude that our stomach has to have hydrochloric acid as well as pepsin/enzymes for it to digest food. The only reason the powerful acid doesn't burn through our stomach is because we have a mucus lining on the sides of our stomach, and it grows back if the lining gets damaged. Today, we also learned that the lower the PH a substance has, the more acidic it is. We also did a mini experiment of testing all our tubes for their PH. In conclusion, a mixture of acid and enzymes are what is required to proceed with digestion in the stomach.
